La57

138.9B5

10.81

17

35.45

8

16.00

92

238.0

90

232.0

53

126.9

68

167.3ErIThUOCl

DENNIS J. CLOUTHIER, ROBERT GRIMMINGER, and BING JIN, Department of Chemistry, University of Kentucky, Lexington, KY;

PHILLIP M. SHERIDAN, Department of Chemistry and Biochemistry, Canisius College, Buffalo, NY.

THE X2BO and X2BS (X = HYDROGEN OR HALOGEN) FREE RADICALS

BORON CONTAINING FREE RADICALS

http://www.buzzle.com/img/articleImages/276159-50511-8.jpg

BC

BS2

BH2

BF2

BCl2

HBF

HBCl

HBBr

X2BO

X2BS

COLUMBUS MEETING 1964

OSU Knowledge Bank http://kb.osu.edu/dspace/handle/1811/14522 Dr. C. Weldon Mathews

BF3 + O2 BO2 + F2BO

EXPERIMENTAL BACKGROUND

1. The Emission Spectrum of the BOF2 Molecule, C. Weldon Mathews and K. K. Innes, J. Mol. Spectrosc. 15, 199 (1965).

2. The 4465 Å Emission Spectrum of the BOF2 Molecule, C. Weldon Mathews, J. Mol. Spectrosc. 19, 203 (1966).

3. B atoms, B2 and H2BO Molecules: ESR and Optical Spectra at 4 K, W. R. M. Graham and W. Weltner, Jr., J. Chem. Phys. 65, 1516 (1976).

H2BS, F2BS, Cl2BO, Cl2BS experimentally unknown!

H2BO MO PICTURE

b2 n(O)

b1 (BO)

a1 (BO)

X 2B2 ...(a1)2 (b1)2 (b2)1

~

~

~

B 2A1 ...(a1)1 (b1)2 (b2)2

A 2B1 ...(a1)2 (b1)1 (b2)2

.

F2BO SYNTHESIS FOR JET SPECTROSCOPY

BF3 + O2 + Argon

SPECTRA OF JET-COOLED F2BO

WAVENUMBER (cm-1)

22355 22395 22435 22475 22515

2D Graph 3

Short gate LIF

Long gate LIF

Sync-scan LIF

000

41 61

1 1**

Dr. Bob Grimminger

WAVENUMBER (cm-1)

15000 17000 19000 21000 23000

21

B XB A00

11 31

00

3132

11

~ ~~ ~

62

x3

Simulation

Experiment

0-0 BAND EMISSION SPECTRUM OF F210BO

CCSD(T)/aug-cc-pVQZ

Dr. Phil Sheridanx3

WAVENUMBER (cm-1)

22384 22386 22388 22390 22392 22394

Observed

Simulated (32K)

HIGH RESOLUTION 0-0 BAND OF F2BO

Simulation: B3LYP/aug-cc-pVQZ rotational and spin-rotation constants only

MOLECULAR STRUCTURES

1.365 Å

1.314 Å

121.4 X 2B2

~

A 2B1

~

+0.04 Å

-0.002 Å

+1.4

B 2A1

~

+0.01 Å

-0.005 Å

+0.12

THEORETICAL PREDICTIONS FOR NEW RADICALS

1. B3LYP and CCSD(T) geometry optimizations and frequency calculations with

aug-cc-pVnZ (n = 3,4,5) basis sets.

2. Energies extrapolated to complete basis set limit (CBS) using

E(n) = ECBS + Ae-bn (n = 3, 4 or 5 as above).

3. Franck-Condon simulations of the vibrational structure of absorption and

emission spectra.

4. Rotational band contour calculations using ab initio A, B, C and aa, bb, and cc

constants.

Tests on F2BO:

T0 (B state) error = +32 cm-1

T0 (A state) error = -62 cm-1

X state vibrational freqs max error = 14 cm-1

~

~

~

Franck-Condon simulations of absorption and emission

spectra

Wavenumber (cm-1)

-20 -10 0 10 20

H2BO

PREDICTIONS FOR THE H2BO and H2BS FREE RADICALS

Calculated rotationally resolved contour of the 0-0 band of H2BO @ 10 K

Ene

rgy

(kca

l/mol

)

0

10

20

30

40

C2v TransCis

H2BO ISOMERS

B + H2O HBOH Matrix IR

G. H. Jeong, R. Boucher, and K. J. Klabunde, JACS 112, 3332 (1990)

LIF IDENTIFICATION OF F2BS

F2BS prepared in a BF3/CS2/Ar discharge

Dr. Bing Jin

SYNTHESIS AND IDENTIFICATION OF Cl2BS

Cl2BS produced by a discharge through a BCl3/CS2/Ar precursor mixture

Cl2BS LIF spectrum

Wavenumber (cm-1)

21000 21200 21400 21600 21800 22000 22200

000

110

Cl2BS 0-0 band emission spectrum

Wavenumber (cm-1)

15000 16000 17000 18000 19000 20000 21000 22000

LaserB-A emission~ ~

B-X emission~ ~

310

310

101

Simulation B3LYP/aug-cc-pV5Z

T 0 (c

m-1

)

0

5000

10000

15000

20000

25000F2BO F2BS Cl2BS

32 cm-1

62 cm-1

56 cm-1

18 cm-1

147 cm-1

93 cm-1

X 2B2

A 2B1

B 2A1

~

~

~

EXPERIMENTAL VS AB INITIO T0 VALUES

F2BO, F2BS: CCSD(T)/CBSCl2BS: CCSD(T)/aug-cc-pVTZ

Ab Initio =

CONCLUSIONS

1. The LIF and emission spectra of jet-cooled F2BO have been

observed and analyzed.

2. Ab initio calculations have been performed to calculate the

spectra of other X2BO and X2BS radicals.

3. Extensive searches have failed to reveal the spectra of H2BO

and H2BS.

4. The previously unknown F2BS and Cl2BS free radicals have

been observed and their electronic spectra studied.